From e82485c566e7dd17946dfeda4e58ea3ac353eca8 Mon Sep 17 00:00:00 2001 From: Simon Josefsson Date: Tue, 20 Apr 2010 11:31:26 +0200 Subject: [PATCH] visibility: Don't use -fvisibility if it leads to a warning. --- ChangeLog | 8 ++++++++ m4/visibility.m4 | 26 ++++++++++++++++++++++++-- 2 files changed, 32 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index fa879e924..d4f1a6a45 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2010-04-20 Simon Josefsson + Bruno Haible + + visibility: Don't use -fvisibility if it leads to a warning. + * m4/visibility.m4 (gl_VISIBILITY): Check whether -Werror is usable. If + yes, don't pretend that visibility works if it leads to a warning. + Reported by Mike Gran . + 2010-04-20 Andreas Gruenbacher * build-aux/bootstrap: Use "git -h" for testing for supported options diff --git a/m4/visibility.m4 b/m4/visibility.m4 index 6d3f9c9d9..077c4765e 100644 --- a/m4/visibility.m4 +++ b/m4/visibility.m4 @@ -1,4 +1,4 @@ -# visibility.m4 serial 2 (gettext-0.18) +# visibility.m4 serial 3 (gettext-0.18) dnl Copyright (C) 2005, 2008-2010 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -26,15 +26,37 @@ AC_DEFUN([gl_VISIBILITY], CFLAG_VISIBILITY= HAVE_VISIBILITY=0 if test -n "$GCC"; then + dnl First, check whether -Werror can be added to the command line, or + dnl whether it leads to an error because of some other option that the + dnl user has put into $CC $CFLAGS $CPPFLAGS. + AC_MSG_CHECKING([whether the -Werror option is usable]) + AC_CACHE_VAL([gl_cv_cc_vis_werror], [ + gl_save_CFLAGS="$CFLAGS" + CFLAGS="$CFLAGS -Werror" + AC_TRY_COMPILE([], [], + [gl_cv_cc_vis_werror=yes], + [gl_cv_cc_vis_werror=no]) + CFLAGS="$gl_save_CFLAGS"]) + AC_MSG_RESULT([$gl_cv_cc_vis_werror]) + dnl Now check whether visibility declarations are supported. AC_MSG_CHECKING([for simple visibility declarations]) AC_CACHE_VAL([gl_cv_cc_visibility], [ gl_save_CFLAGS="$CFLAGS" CFLAGS="$CFLAGS -fvisibility=hidden" + dnl We use the option -Werror and a function dummyfunc, because on some + dnl platforms (Cygwin 1.7) the use of -fvisibility triggers a warning + dnl "visibility attribute not supported in this configuration; ignored" + dnl at the first function definition in every compilation unit, and we + dnl don't want to use the option in this case. + if test $gl_cv_cc_vis_werror = yes; then + CFLAGS="$CFLAGS -Werror" + fi AC_TRY_COMPILE( [extern __attribute__((__visibility__("hidden"))) int hiddenvar; extern __attribute__((__visibility__("default"))) int exportedvar; extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void); - extern __attribute__((__visibility__("default"))) int exportedfunc (void);], + extern __attribute__((__visibility__("default"))) int exportedfunc (void); + void dummyfunc (void) {}], [], [gl_cv_cc_visibility=yes], [gl_cv_cc_visibility=no]) -- 2.11.0